1. Field of the Invention
The present invention relates generally to a audio-visual system. Particularly the present invention relates to an audio-visual system including a bus for interconnection of various components thereof.
2. Description of the Related Art
Recently, audio-visual (AV) systems have been introduced in which control of various system components may be effected in accordance with operating instructions sent to an audio-visual center. FIG. 17 shows an example of such an conventional AV system with connecting bus.
In FIG. 17 an AV center 1 (such as a television monitior, or the like) is connected to a plurality of image sources 2a, 2b and 2c, which may, for example, include a video tape deck, a tuner, satellite decoder, etc. The AV center 1 is connected individually to each of the image sources 2a, 2b, 2c, respectively, via signal cables 3 which generally include an video signal cable and an audio signal cable (left and right audio cables may be provided for stereo audio). In addition, the AV center 1 is connected in series to the image sources 2a-2c via bus cables 5 interconnected via connectors 4. The bus cables generally include a - balance cable, + balance cable and ground cable. It will be noted that each of the image sources are provided with two connectors 4 for allowing series connection of the components and that a first (i.e. input) side connector 4, as well as the connector 4 of the AV center 1 are provided with end resistance means 6. The end resistance means 6 of the image sources 2a-2e are designed so as to be defeated in the case wherein bus cables are connected to both input and output sides of the component (2a-2c), and the end resistance 6 of the AV center 1 is defeated according to the presence of a bus cable (output) being connected thereto. Thus, according to the system of FIG. 17, the end resistance means 6 of the AV center 1 as well as of the image sources 2a and 2b are inactive due to the presence of the bus cables 5, while the end resistance 6 of the image source 2c is active, since no bus cable 5 is connected to the output side thereof.
According to the system as described above, sufficient control of the AV system is possible. However, recently, since such sophisticated bus systems are becoming increasingly part of ordinary AV products, there is a desire to simplify interconnection arrangements for AV components in order to allow the average consumer to utilize such products with a minimum of confusion.
For example, in the system described above, there is an obvious one to one correspondence between the signal cables 3, the AV center 1, and each of the image source components 2a, 2b and 2c. However, with respect to the series connection of the bus cables 5, such one to one correspondence is not readily evident and misinstallation may easily occur when such connections are effected by a non-professional, since the way in which the signal cables are connected is not analagous to the manner in which the bus cables 5 are connnected. Thus, there is a tendency, for example, for a user to connect a bus cable to the output side of the final component in the system (i.e. 2c) rendering the end resistance means 6 of the system inoperative, leading to malfunction of the bus system overall.
Thus it is desirable to provide an AV system including bus functions, in which the connection between each respective component and the AV center 1 is the same for all components. Thus, confusion between signal cable interconnection and bus system interconnection may be avoided and ease of use for the consumer is greatly enhanced, while sophisticated functioning of the AV system overall need not be compromised.